Objective To investigate the clinical effect of 3D printing assisted pedicle screw placement combined with improved posterior lumbar interbody fusion(PLIF)in the treatment of degenerative scoliosis.Methods From March 2020 to March 2022，47 patients with degenerative scoliosis admitted to the Spinal Surgery Department of Chengyang District People’s Hospital in Qingdao were randomLy divided into an observation group and a control group.The control group consisted of 23 patients，including 11 males and 12 females with an age range of 54~76 years and an average age of (63.09±6.22)years.The patients of control group underwent conventional posterior pedicle screw fixation and PLIF surgery.The observation group consisted of 24 patients，including 11 males and 13 females with an age range of 51~72 years and an average age of (60.64±5.65)years.The patients underwent posterior pedicle screw fixation and modified PLIF surgery with the preoperative use of 3D printing technology to develop a surgical plan while preserving the posterior longitudinal ligament complex.The surgical time，fluoroscopy times，screw placement time，intraoperative blood loss，postoperative drainage volume，Japanese orthopaedic association(JOA) spinal cord function score，visual analogue scale(VAS) pain score，Oswestry disability index(ODI)score changes at preoperative，1 month，6 months，and 12 months，Cobb angle changes at preoperative and final followup，screw placement status，and occurrence of complications were compared between the two groups.Results The measurements of the actual diameter and length of the pedicle screws，the distance from the entry point to the posterior midline，and the pedicle screw angulation in the observation group were similar to the preoperative measurements of the pedicle screws，with no statistically significant differences (P＞0.05).The observation group had significantly higher acceptable and accurate screw placement rates during surgery compared to the control group (P＜0.05).The observation group had significantly shorter surgical time，fewer fluoroscopy times，shorter screw placement time，less intraoperative blood loss，and lower postoperative drainage volume compared to the control group (P＜0.05).All patients underwent follow-up for an average of (13.20±2.51)months，with a follow-up period of 12~18 months.The observation group had significantly better VAS scores，JOA scores，and ODI scores at 1 month，6 months，and 12 months postoperatively compared to the control group (P＜0.05).In terms of complications，the observation group had significantly better outcomes than the control group (P＜0.05).Conclusion The application of 3D printing assisted screw placement combined with improved PLIF in the treatment of degenerative scoliosis can significantly reduce surgical time，fluoroscopy frequency，screw placement time，intraoperative bleeding，and postoperative drainage volume，improve surgical efficiency and safety，effectively reduce secondary trauma and fluoroscopy radiation damage caused by surgery，protect the physical health of surgical staff and patients，and effectively alleviate postoperative pain of patients.It also has a significant promoting effect on the recovery of postoperative spinal function in patients，and can to some extent reduce the occurrence of postoperative complications.